Hi!
I'm using a trackpad on a mac, and I would like Emacs to behave like other applications.
In macOS, scrolling slowly scrolls the display very little and smoothly (even less than a line, for applications that support it). Whereas, if I scroll fast, large amount of text is moved. One big advantage of this is that it's easier for the eye to follow the scrolled text when it scrolls smoothly. When the text jump (as it does by default in Emacs) it's easy to loose track of what is what on the screen, and you wast time trying to find visual markers on the screen.
To get the smooth scroll, I have used the settings suggested by the original poster for `mouse-wheel-scroll-amount': (1 ((shift) . 5) ((control) . nil)) I have always seen the old setting as a relic from the time when computers weren't powerful enough to perform scrolling effectively.
However, `mouse-wheel-progressive-speed' should be `t' -- at least when using a trackpad. If not, it's not possible to scroll fast through a buffer. (In numbers, I can scroll through a 2000 lines file in three strokes when it is set to `t', but it would require about 60 strokes when nil -- which clearly makes it utterly useless.)
TL;DR: When using a trackpad or a magic mouse on macOS, the following settings are suitable:
mouse-wheel-scroll-amount: (1 ((shift) . 5) ((control) . nil))
mouse-wheel-progressive-speed: t
-- Anders